Shielded, explosively released fastener



June I, 1954 P. P. SMITH SHIELDED, EXPLOSIVELY RELEASED FASTENER Filed June 15, 1951 M FL Patented June 1, 1954 UNITED STATS are OFFICE SHIELDED, EXPLOSIVELY RELEASED FASTENER Phillips P. Smith, San Antonio, Tex., assignor to the United States of America as represented by the United States Atomic Energy Commission 1 Claim. 1

This invention pertains to a jettisonable fastening device and more particularly it refers to explosive bolts and tie rods.

At times it is expedient to attach one body to another in such a manner that subsequent detachment is possible by remote means. One example is where equipment is temporarily attached to a radioactive body. The radioactive contamination of the equipment precludes the possibility of personnel later approaching the equipment with impunity. In such circumstances, it has been found that an explosive bolt may be used for attachment which may be detonated by remote means such as by electric current applied to the charges through permanently connected wires.

It is an object of this invention then to provide an explosive bolt that serves as an efiective fastening means but, when exploded, effectively releases the equipment or body it has been securing so that the latter can readily be removed.

Other objects will appear from the following description together with the figures, in which:

Figure 1 is a longitudinal sectional view, partly in elevation, of a device embodying the invention; Figure 2 is an end view of the device; and

Figure 3 is a sectional view taken on the line 33 of Figure 1.

The device is generally indicated at In in Figure 1, disposed between two bodies or plates l2 and 14. Being variously termed a jettisonable fastening device or simply an unfastening device, it comprises a bolt, strut, or tie rod [6 and a shield or spacer l8.

The bolt or tie rod 16 is mounted between the plates 12 and 14 through which it extends in apertures 20 and 22, respectively. Each end of the tie rod 18 is threaded externally at 24 and 26 on which are disposed nuts 28 and 30, respectively. Extending from each end of the rod i6 is a bore or chamber 32 and 34, the external ends of which are internally threaded at 36 and 38, respectively. Within these threaded ends is disposed a plug 49 which is identical for each chamber 32 and 34. The plug 40 has a central passage 42 disposed on the longitudinal axis of the rod [6 which is adapted to pass permanent electric wires (not shown in the drawing) for detonating purposes.

The chambers 32 and 34 are adapted tov contain explosive charges indicated at 44 and 46, respectively. When it is desired to rupture the bolt [6 one or both of the explosive charges 32 and 34 are detonated by energizing the appropriate electric wires 50 and 52 or 54 and 56 pass- 5 ing into the charges,

It may be desirable to detonate only one charge of explosive first and employ the second charge only in the event the first charge fails to rupture the bolt it. Under these circumstances, the second charge may be more powerful than the first so as to insure complete rupture of the bolt.

Though the bolt i6 is shown with removable nuts on both ends, obviously one of the nuts 28 or St may be integral with the bolt to provide a head.

The spacer or shield I8 is provided to hold the plates l2 and It at predesigned distances from each other. In addition, the spacer [8 serves as a shield for flying fragments resulting from the explosions, for which reason it is cylindrical and disposed about the bolt It. A plurality of apertures 48 are disposed over the surface of the shield It in order to permit the escape of expanding gases due to the explosion. These apertures are small enough to serve this purpose while blocking the passage of explosion fragments.

It will be understood that the invention is not limited to the specific embodiment disclosed, inasmuch as other embodiments thereof will be readily apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claim.

What is claimed is:

In combination, two members spaced from each other, a tie rod located between the members and having an explosive charge in each end thereof, means for separately detonating each charge, a shield surrounding the rod and engaging the members and having an internal diameter greater than the outer diameter of the tie rod so as to cause the shield to be spaced from the rod on all sides, the shield having a plurality of apertures disposed over its entire surface, and means on each end of the rod for attaching the rod to each member and for maintaining the members in engagement with the shield so as to support it in spaced relation to the rod.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,725,473 Page Aug. 20, 1929 1,835,243 Schaffert Dec. 8, 1931 2,315,799 La Guardia et a1. Apr. 6, 1 3

FOREIGN PATENTS Number Country Date 694,019 Germany June 27, 1940 875,291 Germany Sept. 14, 194:2 

